We wrote this book because Elasticsearch needs a narrative. The existing
reference documentation is excellent—as long as you know what you are
looking for. It assumes that you are intimately familiar with information-retrieval concepts, distributed systems, the query DSL, and a host of other
topics.

This book makes no such assumptions. It has been written so that a complete
beginner—to both search and distributed systems—can pick it up and start
building a prototype within a few chapters.

We have taken a problem-based approach: this is the problem, how do I solve
it, and what are the trade-offs of the alternative solutions? We start with the
basics, and each chapter builds on the preceding ones, providing practical
examples and explaining the theory where necessary.

The existing reference documentation explains how to use features. We want
this book to explain why and when to use various features.